The present invention relates to a semiconductor device, in particular, to a technology effective when applied to a semiconductor device including a solid state image sensor.
When an image sensor (picture element) to be used in digital cameras or the like has a large chip size in order to have an improved image quality, divided exposure treatment is performed a plurality of times during a manufacturing step of it because single exposure treatment is insufficient for the exposure of the entire chip.
It is known that in a solid state image sensor used in digital cameras having an autofocus system function to which an image-plane phase-detection technology has been applied, a plurality of pixels configures the image sensor and they are each equipped with two or more photodiodes. In this case, at the time of focusing, two photodiodes in a pixel having one microlens have an equal imaging output in principle.
Patent Document 1 (Japanese Unexamined Patent Application Publication No. 1994-324474) describes discrete and irregular arrangement of pixels at the connection making inconspicuous image abnormalities at the connection due to divided exposure.
Patent Document 2 (Japanese Unexamined Patent Application Publication No. 1997-190962) describes a boundary of divided exposure in nonlinear form.
Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2003-005346) describes a method of dividing a pixel pattern with a zigzag dividing line into a plurality of divided regions and forming a double exposure pattern, which is a pattern exposed doubly, between the divided regions adjacent to each other.
Patent Document 4 (Japanese Unexamined Patent Application Publication No. 2014-102292) describes a photomask having an overlapped region between two divided regions and equipped with a plurality of light shielding patterns, a light transmission portion, and a light reduction portion. The light reduction portion has a light transmittance greater than that of the light shielding pattern and smaller than that of the light transmission portion.
Patent Document 5 (Japanese Unexamined Patent Application Publication No. 2008-008729) describes a connector exposure region placed so as to locate the width-direction center of the connector exposure region at the center on a line connecting the respective centers of oscillators above and below the connector exposure region.